what is the problem

P0031 = Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1). Diagnostic Trouble Code could be cause by one or more of the following: * A short or open in the heater circuit in the sensor. * A failed O2 sensor heater. * Wiring/connectors broken/frayed leading to sensor and/or relay. * Failed PCM/ECM.